A german U-Boat sunk the Lusitania because it was carrying ammunition to Britian, their enemy.
The Lusitania was sunk because the Germans thought that it was carring more than just passengers. The Germans thought that Great Britain were smuggling in weapons to help them fight the war. There...
The Lusitania was sunk May 7, 1915 when a German torpedo hit the British ocean liner.
It was sunk by a German U-Boat.